Nowhere really. He essentially becomes more and more of a thug who always causes trouble and constantly keeps on gambling. He becomes some of kind of leader to all the mages of Fenris territory since they are all basically slaves(except Vanessa). However, he does have his moments where he shine. One time, he gambled with a priest and won continuously so feeling wronged, that priest unconsciously called upon the Goddess to win the game but Alfoi still manages to win because the God couldn't stay for long. Other time, Ghislain and the Continent's other 7 strongest collectively fought against a dragon but their plans almost went up in smoke however, Alfoi somehow manages to prevent the Dragon from attacking even though he was only a 5th-circle while the Dragon was 9th-circle allowing Ghislain and others to win more 'easily'.

Right you are. In the novel, Gillian almost died with his chest pierced. Though it may differ in the manhwa since no mages or priest was present in the novel when they fought.

maybe you read it in demonicscans.